Pete Jarman wrote:
Ron wrote:
<The only way to make a decent CPNC system with a windows GUI is to
use a
<separate motion controller box to handle the real time stuff. We had
<some discussions here a few weeks ago about developing such a box,
but
<that died.
Is there any way that the motion controller box could be an outdated
x86 PC
with an interface card running a real time programme under either DOS
or
linux? The software would handle incoming commands and report status
through
the serial port to the controlling PC running the GUI and the
conversational
programming software.
Yes, in theory, a DOS program that makes no system calls, and has no TSR
programs that
might grab control away will be allowed to run unimpeded, and can
achieve real time
performance. The serial port might be a bit slow for this. But, if you
are throwing Linux
into the equation, who needs any extra computers? They just make
debugging that much
more of a hassle. If you will be using Linux, put everything on it, the
real-time motion
control will make sure it has adequate time to process the motion, and
the rest is left
to the user's various tasks. I do this now, and pretty fearlessly edit
programs while the
machine is running others. (The only problem is that while you are in
another window,
you lose keyoard and mouse focus to the machining task, so the only
emergency
control is the E-stop button, which is a bit drastic. Nothing like
trying to switch focus
with the mouse when a crash is 1/2 second away!)
Jon
